The invention is related to a method and composition of matter for the concentration and separation of trivalent, tetravalent and hexavalent elements, such as actinide and/or lanthanide values, from samples containing these and other elements. More specifically, the invention relates to a method and apparatus for the quantitative recovery of actinide and/or lanthanide values from biological and environmental samples. Still, more specifically, this invention relates to a new extraction chromatographic resin which is especially suitable for the extraction of trivalent, tetravalent and hexavalent actinides (Th, U, Np, Pu, Am, and Cm) and/or lanthanides from soils, surface and ground waters and bioassay samples and for the isolation of radium from environmental samples.
The recovery and isolation of radionuclides from environmental and bioassay samples is complicated by the presence of silica, aluminum and iron (III) as well as other frequently present ions such as titanium, bismuth and phosphate. The isolation of the actinides, lanthanides and radium from such samples in the past has involved time-consuming, expensive and sometimes hazardous procedures.
A number of previously described procedures for the determination of the actinide plutonium in urine, for example, involved preconcentration of small amounts of Pu from the vast excess of matrix substances present in urine samples by precipitation reactions, adsorption on glass fibre, extraction, extraction chromatography or ion exchange. Of these, precipitation reactions appear to provide the most satisfactory results.
However, such methods are complex, time consuming and relatively expensive.
U.S. Pat. No. 4,548,790 dated Oct. 22, 1985 describes a group of neutral bifunctional organophosphorus compounds broadly described as alkyl(phenyl)-N, N-dialkylcarbamoylmethylphosphine oxides (hereinafter referred to as CMPO) which are useful for the recovery of actinide and lanthanide values from acidic solutions containing these and other metal values. The combination of the CMPO extractants with a phase modifier such as tri-n-butyl phosphate in a normal paraffin hydrocarbon diluent is described in U.S. Pat. No. 4,574,072. U.S. Pat. No. 4,835,107 describes passing samples in a mineral acid solution through a separation column of an alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxide dissolved in tri-n-butyl phosphate on an inert support to selectively recover actinides. These patents are assigned to the common assignee and are incorporated herein by reference.